Many systems using the AC power line as a communication pathway have been available at reasonable cost for several years. They use both analog and digital communication techniques. They are not compatible with each other and their reach includes all of the power circuits that are derived from a single distribution transformer. This means that several homes on the same street may have conflicting systems.
One popular system is the X10 system by BSR that is used to provide low speed digital communications in the home for various applications including: